Pulsation dampeners are devices known and used in the art for controlling unwanted pressure changes in a liquid within a fluid handling system. Such pressure changes are caused by sudden fluid flow changes that can be repeating, e.g., such as those caused by operation of a reciprocating positive displacement pump, or that can be single events, e.g., such as that caused by a pump start up or a sudden valve closure. The sudden acceleration or deceleration of a fluid in a pipeline by these events causes a flow variation, which is an uncontrolled form of kinetic energy that can be seen in pipe shock or vibration. This energy continues to rock back and forth in a fluid handling system until it dissipates through friction loss or causes damage to the fluid handling system itself. This occurs because fluids or liquids are not compressible.
Pulsation dampeners are devices known in the art that use potential energy to absorb these flow variations and smoothly meter out the fluid within the fluid transport system. Typically, pulsation dampeners are used to control repeated, cyclic or “pulsed” flow variations in a fluid transport system. However, pulsation dampeners can also be used to control a nonrepeated, single event or “surge” flow variation in a fluid transport system.
Pulsation dampeners known in the art typically comprise a nonperforated housing body that defines a fluid chamber therein. Fluid is directed into the chamber via fluid inlet opening in the housing. Pulsation dampeners can be configured having an “appendage” design, where the device is attached as an appendage to a designated fluid handling system. In an appendage design, the pulsation dampener housing body has a single opening to the chamber that serves as both a fluid inlet and a fluid outlet to provide two-way fluid flow through the device. Alternatively, pulsation dampeners can be configured having a “flow-through” design, where the dampener is attached in-line with the designated fluid flow device. In a “flow-through” design, the pulsation dampener housing body has a fluid inlet opening and a separate fluid outlet opening to accommodate one-way fluid flow through the device.
Known pulsation dampeners include a compressible member, e.g., an elastomeric bladder, disposed within the fluid chamber. The bladder is configured to occupy a desired volume in the chamber and is gas pressurized for the purpose of providing a desired degree of pulsation dampening. The bladder can be attached in some fashion to the chamber, and includes a pressure valve that is preferably accessible through the housing body for adjusting the bladder gas pressure externally from the housing.
Such pulsation dampeners are attached within a fluid transport system with the fluid inlet connected in fluid flow communication with the fluid being transported through the system. Most pulsation dampeners are installed inline with the suction and discharge piping or “teed” as an appendage. Appendage type pulsation dampeners are commonly used in a majority of applications characterized by low-frequency pulsed fluid flow variations due to their relatively low cost and ease of installation, e.g., they are usually teed into the piping system. The inherent design of such appendage type pulsation dampener operates to limit the practical, i.e., cost effective, effectiveness of the design in controlling high-frequency flow variations. Thus, “flow-through” type pulsation dampeners are most effective in fluid handling applications characterized by high-frequency pulsed fluid flow variations, as the flow through design provides a quickened or increased speed of response.
In an example application, an appendage type pulsation dampener is attached to a fluid transfer pipe downstream of a reciprocating pump, in communication with the fluid being passed through a fluid transport pipeline. In this service the pulsation dampener operates to control a sudden surge or pulsation of fluid flow in the fluid pipeline as follows. When a sudden surge or pulsation of fluid pressure exits the pump and enters the pipeline, it also enters the pulsation dampener chamber via the housing body fluid inlet. Within the chamber, the bladder operates to buffer or dampen the incoming flow variation in a manner that attenuates the flow variation through the remaining portion of the fluid transport pipeline coupled to the pulsation dampener.
Although such above-identified pulsation dampeners are widely used, they are not well suited for use in certain demanding fluid handling applications. An example of such a demanding fluid handling application is large-scale fluid handling, e.g., piping or other types of fluid handling systems that are characterized by high-frequency flow variations. As mentioned above, due to their inherent design, appendage type pulsation dampeners do not provide a sufficient speed of response to absorb the high-frequency flow variations. While flow-through type pulsation dampeners are sufficiently responsive in absorbing high-frequency flow variations, the large cost associated with making a sufficiently sized dampener for service in such large scale applications is economically prohibitive.
It is, therefore, desired that a pulsation dampening device be constructed in a manner capable of providing pulsation dampening service in demanding fluid handling applications characterized by high-frequency flow variations, calling for a dampening device having a rapid speed of response. It is also desired that such a pulsation dampening device be capable of being used with other such devices, if so desired and necessary, for purposes of providing a pulsation dampening system for use in addressing the pulsation dampening requirements of such demanding fluid handling applications.